a decision support system for water resource...

A DECISION SUPPORT SYSTEM FOR WA-rER RESOURCEMANAGEMENT IN L1FOU ISLAND, NEW-CALEDONIA

Didier LILLE (*), Christian JOST (**)

(*) IRD, The French Research Institute for Development - Remote Sensing Laboratory,LATICAL - BP A5, Noumea, New-Caledonia

Ph. (687) 26 0835 Email: [email protected](**) University of New-Caledonia, Geography Laboratory GECO, BP 4477,98847 Noumea,

Ph. 687-265847 Fax: 687-263826 Email: [email protected] of Sydney, School of Geosciences, Geography F09, 2006 NSWPh. 61-293516463 Fax. 61-2 9351 3644 Email : [email protected]

Abstract

ADAGE l is an innovate program for decision support in environmental development andmanagement developed since 1996. Based on the fact that the scientific expertise does nothave a vocation to give the answers to the problems posed by the decision maker,representing the civil society, ADAGE was developed on the idea of implementing data andexpertise in the field of decision-making and integrated into the responsibility domain in anunderstandable and usable new tool. ADAGE makes the interface between the domain ofobservatories - studies and scientific actions that allow the knowledge to emerge of thephenomena - and the domain of the political strategy, political power and social pressure.These two domains have their indicators, their concepts, their culture and their behaviour,origin of misunderstanding and conflicts.

Developed as prototype in three regions (French Guyana, Portugal, Western France) aboutthree environmental problems (Water quality, Waste management, Water rehabilitation of aharbour), this original approach was developed in New Caledonia (south-western Pacific) in1999 for a sustainable management of the water aquifer of Lifou Island. This paper proposesto explicit this project by the way of the description of one of the products: the DecisionSupport System. This tool uses or simulates various kind of knowledge, from the SPOTsatellite data to real-time watch-over of the resource, from the social and cultural behaviourand reactions of the population to the politics' indicators, while using artificial intelligencetechnologies.

ADAGE Concept: FRANl;OIS Nadine (ALCATEL), HUYNH Prederic (IRD), LlLLE Didier (IRD), NOEL Jacques (IRD).POLlDORI Laurent (lGN).

10th Australasian Remote Sensing and Photogrammetry Conference

IntroductionAn European consortium with complementary skills: IRD (France, ex ORSTOM),ALCATEL Space Industries (France), EID (Portugal) and the Common Centre of Researchof the European Commission (Italy) have been developing since 1996, an innovate project fordecision support in environmental development and management (ADAGE: Aide a laDecision en Amenagement et Gestion de l'Environnement).

The ADAGE concept isbased on the fact that thescientific expertise doesnot have a vocation togive the answers to theproblems posed by thedecision maker,representing the civilsociety. ADAGE does notreplace the analyticalprocesses and observationand even more thedecision process, butpresents itself as anapproach forcommunication andnegotiation, where eachdomain has its role toplay.For the originality of theapproach, ADAGE hasobtained the EuropeanEUREKA label (EUI299)in 19961

•

Fig.1 ADAGE first threenrototvoe nroiect

Three environmental problems were kept for the development of prototypes: therehabilitation of the quality of the water of a harbour' (Brest, France), the collect,management and elimination of selective wastes in a context of urban development' (Lisbon,Portugal), and the management of used water and rainwater in an urban area facing drainingproblems" (Cayenne, French Guyana).The existence of this interface allows the mutual comprehension of the objectives andprocesses of each party (the decision-makers and the political managers of a human, scientificand technical society, in charge of the corporation of knowledge mastery). Furthermore, thisputting together of concepts and indicators is the necessary basis for a simulation of theimpact and consequences of the decision, accepted by each of them. The ADAGE filterconstructs a consensus of a solution, presented on the one and other hand with accepted andknown concepts: the social dimension of the problem is taken into consideration.

J 23 Head of project: Nadine Francois (ALCATEL), Jacques Noel (lRD)4 Head of project: Frederic Huynh (IRD)

10th Australasian Remote Sensing and Photogrammetry Conference 62

This approach was, for the first time, developed in the South Pacific in 1999, for sustainablemanagement of the fragile water resource of LIFOU Island 5, in New-Caledonia. Since the setup of the prototype, developed in above quoted regions, the tool, called Demonstrator, hasbeen strongly and deeply improved (D. Lille) noticeably with the integration andspatialization of social, cultural and environmental data collected and analysed through anoriginal approach based on cultural geography (c. lost).

Fig.2 Lifou Island - Loyalty Islands - New Caledonia

This paper proposes to explicit this project with the description of one of its products: theDecision-Support System. This tool uses or activates multidisciplinary knowledge andprocessed figures, from the SPOT satellite data to real-time watch-over of the resource, fromthe social behaviour and reactions of the population to the politics' indicators, while usingartificial intelligence technologies.Why a Project for sustainable managementof ground water of LlFOU island?Because of a lack of surface drainage on this uplifted calcareous atoll, the ground water ofLifou island is the unique source of drinkable water. Extended on 119,600 hectares the islandis homing 9,614 permanent residents and has a density of 8.2inhablkm2• A dynamicdemography and the numerous projects of development have absolutely to be confrontedwith a coherent management of this resource. Major actress of the island's ecosystem, thewater lens undergoes numerous aggressions related to human activities whose impacts, today,are still not disastrous, mainly due to the weak density of the population (8.2inhablkm2) .

Moreover, the continuation of present behaviour and bad habits regarding waterconsumption, added to the increasing demographic pressure and a legitimate economicaldevelopment, are contributing to endanger the resource with time. Therefore, factors ofpresent and future aggressions require to be identified and analysed. The actions to start up

5 Head of project: Didier Lille (lRD)


with must be specified and a management tool for the ground water needs to be set up. Itappears a necessity to elaborate a concerted strategy for the management of this soft waterresource, first to master and anticipate consequences of the human activity on the future ofthe ground water, second to use and allow an optimal evolution of the water conveyancenetwork.

Organization of the project

Coordination BoardI Fig.3 Organization of the project

OrientationsStrategyCommunicationConception of indicators for decision-makingAoorooriation bv oooulation & deciders

Project Board

Technical choicesConception of the

prototypeCarrying outValidationPlanning

Partners

University of New -CaledoniaA2EPGENSYM

ALCATEL

~~:l~8'i'Q•In order to help orienting the project, a Coordination Board was set up gathering:

Institut de recherchepour le developpernent

• La Province des lles• The Lifou council• Custom Authorities• The ADAGE group

Moreover a Project Board was organised in 11 work units to allow an optimisation ofthe work and constant exchanges between disciplines and thematic through« facilitators ». A particular attention was given to the communication part of theproject for it to be efficient either between thematic research groups than between thescientific community and the institutions. The diffusion of information within thepopulation and the tribes was organised through the customary authorities. Allexisting formal or informal circuit of communication were and are still used (schools,women rights association, men of God, customary chiefs, ... )


Data in the decision-making process

The task of inventorying and analysing the environmental data allows to guarantee that theavailable data will provide relevant and useable information for the decision-making process.It plays then a role of filter between:

• Upstream: the collect of existing data and the creation of new data• Downstream: in the integration of data into the tools to help decision-making

(dashboard, impact simulator, communication support system..)

Environmental data about Lifou have only been partly collected and gathered in accordanceto the aim of the project. This is the case of the studies conducted by the "Social sciences andEnvironment Unit2

" , which released and spatialized new data on population perception andbehaviour, on the risks and threats to the water, and on population and economicdevelopment statistics. All the other information have not been created on purpose accordingto the problematic, but were formerly elaborated either with no specific commendation or formanagement purpose not necessarily linked to a ground water study. Therefore it waspredictable that not all data were adapted to the studied problem and this for various reasons:

• Heterogeneity of data: digital accuracy, thresholds, non comprehensive data,incompatible support, reading format, repetitiveness', data file settings,

• Lack of description inp data attributes: non specified units, meaning or non coherenceof attributes, of codes, lack or ambiguous parameters,

• Non adequation between data and aims: level of image processing, projectionsystems, scale, data accuracy,

• Non accessibility of data: non available, loss, confidentiality, prohibitive cost,unknown location of data,

The Decision-Support SystemDeveloped in 02 © OENSYM

SI&RIInformation Server& Interactive ReportDeveloped in HTML and JAVA

- Information support- Questions! AnswersInteractive Cd-Rom Possibility of integrationin an INTERNET Server

••

Fig. 4 Organisation ofthe computed products

Dynamic informationScenarios set upSimulationCommunication

DATAArchives

2 Dr Christian Jost, Head of the "Social sciences and Environment Unit"

1Oth Australasian Remote Sensing and Photogrammetry Conference 65

Description of the Demonstrator• Developed in G2 © GENSYM language• Cartographic basis GIS georeferenced• Data basis object oriented and related to water• Temporal simulations• Running of the peripheral systems• Orientation according to real time

The first problem, quite usual, which came out, was the heterogeneity of data and systemssources, especially among the GIS, the data base management systems and the processingimage systems. The solution that was chosen was to try not to modify any organization, but toestablish dynamic links between the central system and the systems providing data. This wayan independence and a development of the whole procedure is guaranteed. The aim is here toput at disposal an existing yet dispersed (therefore hardly usable) information and not to tryto organize it in a centralized way. This integration processes has been developed genericallyand will be usable via Internet.

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I Fig.6 Partners and their contribution I


Description and use of the demonstrator tool - The global interface

A tool of dialogue and of communication involving multi-actors dealing with:• interactions:

• water and demographic evolution• water and tourism development

• risks and threats for the ground water related to agricultural activities (fertilisers, pesticides,irrigation, ..)• risks for the ground water in respect to cattle breeding and other polluting activities• impact of unauthorised waste dumps• optimisation of the use of drillings and of the water conveyance network• environmental legislation• appropriation of the project by the population• support given to decision-makers

Water Resource Management through aconcerted approach of the Environment ______~#_s _

Information• Concepts and contacts• Partnership• Bibliography

Understanding• Social features and water

system• Phreatic lens• Legal features

Navigation• Conception & Management• Spatial representation• Scenarios & Simulation

IRD - ALCATEL - Universite de NC - Province des lies - Mairie de Lifou - Autorites coutumieres - A2EP

Fig. 7 The dashboard of the demonstrator


Description and use of the demonstrator tool - the GIS interface

A graphic layout, a «Geographic Information System» type:

• predetermined information layers by experts,• a basis of data georeferenced and object oriented,• links with INTERNET.

Sensitivity maps may be exploited differently in the decision process:

• static and compartmentalised presentation of the information, like an atlas,• crossing of information within a system of geographic information (in particular, crossing

between aggression and vulnerability),• dynamic modification enabling the simulation of an evolution of the sensitivity.

- reseau routlerse00ndaire

[::::J reseau routierprincipal

o

bases

image

lentille

Imltes de laressource en eau

Iavorable a l'explOitallon

Legend

l!I Adduction l!I Distribution

Conduites Adduction Eau Potable

• geologle et fracturation

• nappe phreatique : exploitation

e nappe phreatique : vulnerabilite

@ carte de base

• carte pedologique

• couvert vegetal

.. zones antbroplsees

I Fig. 8 Part of the GIS interface


Integration of the information layers specific to the risk notion :

• vulnerability of the environment,• allocation of the resource and limits of exploitation.

Recommended optimalcapacity of waterexploitation (m3/hr)

Fig. 9 Integration of the information layers specific to the risk notion

o

image

bases

lentille

15 • 20 m3,heure

10 . 15m3,heure

20 . 25 m3,heure

10 m31heure

< 10 m31heure

~ Adduction ~ Distribution

Conduites Adduction EauPotable

• image satellite SPOT 1995

\I) carte de base

• carte pedologique

.. couvert vegeUrl

• zones anthroplsees

• geologie et fracturation

@J nappe phreatique : exploitation

• nappe phreatique : vulnerabilite

Major functioning principles of the LIFOU soft water lens' :

Lifou is the largest of the high carbonated islands composing the « Archipel des Loyaute »,

It stretches according to a NW-SE direction, parallel to «la Grande Terre ». It is made up oflimestone build on a volcanic substratum, which does not show on any part of the islandsurface, but acknowledged by geophysics. Schematically, it is a raised atoll supported byage basalts dating back between 9 and 11 million years. The summital reef crown of theisland which shows the beginning of the uplift of the island belongs to the inferiorPleistocene period.

3 Source: Michel Allenbach, in charge of the geological study in ADAGE-Lifou project - University of NewCaledonia


The description of the rocks showing on the surface of Lifou enables to distinguish threetypes of limestone facieses forming two main geomorphologic units:- the limestone build upon the reef crown of the previous atoll to be found at the island'speriphery.- the biomicritic limestone and the biomicritic dolomite are the expression of a lagoonsedimentary filling of an old atoll located in the inland part.Therefore, the porosity of these rocks is different and the rapid lateral variations do not allowan assimilation of this aquiferous environment to a homogeneous one. This makes it evenmore complex to explain its functioning.

The general case of the coastal aquiferous areas:

In most cases, the coastal aquiferous areas are connected to the sea. They are complexaquiferous/sea systems. In such systems, the underground soft water, which flows from thereupstream to the downstream of the ground water, heads to the shore where it drains itself. Itsprogression is limited in depth due to the invasion, in opposite direction, of the sea waterwhich tends to get under the continent. But due to their specific and differing density, thesetwo types of water to be found at a time in the littoral area tend not to mix up. They willactually be superposed. The soft water being less dense" will float" above the more densesea water.

The contact between those two water types is shown by a transitional area more or less thickaccording to local configurations. Its location is determined by a modification of the heightabove the sea (in fact a difference between the hydraulic charges) between the piezometriclevel of the ground water and the zero level (seas average level).

An intense exploitation of the underground water in coastal areas, with flows above those ofsupply, debilitates the piezometric surface. The difference between charges lowers then andthe sea water progressively flows into the aquiferous areas. This shows how important it is tomanage with preciseness the exploitation of coastal ground waters.

LIFOU Island - New-CaledoniaThe water cycle a..

Evalloration

t r:.... Jj Pi';;'''''._~"\~"I~.t· ...

Fig. 10 The water lens of Lifou island

Evaporation

t

Integration of technical information on water networks:

• water conveyance network,• water supply network,• characteristics of the equipment (water tanks, drillings),• simulations of flux

o reseau AEP

Information layers

• Image satellite SPOT 1995

(i carte de base

.. carte pedologlque

• couvert vegetal., zones emhroplsees

Etgeologle et !racturaUon

(I) nappe phreaUque : explo~aUon

• nappe phreaUque : vulnerabll~e

o risques

images

image

bases

lentille

Fig. 11 Integration of technical information on water networks

Population's distribution

An intrinsic temporal dimension:

• ability to simulate behaviours of entities• ability of evolution in real time• ability of building up sequential evolutive reviews

Conduites Adduction Eau Potable

l!I Adduction I!I Distribution

image

bases

lentille

images

o risques

o reseau AEP

@l carte de base

8 carte pedologlque

• couvert vegetal

.. zones anthropisees

El geologle et Iracturation

• nappe phreatique : explottation

tl nappe phreatique : vulnerabiltte

couches d'information

., image satellite SPOT 1995

navigation @ e ®0,

Fig. 12 The distribution of the population

Population and Demography

At the scale of an island like Lifou (l150km2) with an average population density of only 8.4

inhabitants per square kilometre, the demographic pressure on the environment and on theresource remains very weak, in comparison with other islands of the Pacific, such as Guam,Tahiti or Oahu. Despite a relatively weak demographic growth of 2.0% per year, theunequal spreading of the population, the extension of the occupied areas, the increase in thenumber of the infrastructures consuming water, the increase of the needs and the equipmentof households, the development of tourism are nevertheless as many factors contributing toan acceleration of the drawing outs of the water reserve. They also multiply rejects whichcan possibly affect the ground water.

Internal Average Relative Reflectance

This dialog is used to convert raw DN values to relative reflectance. This is done by dividing eachpixel spectrum by the overall average spectrum.

To open this dialog, select Image Interpreter I HyperSpectral Analysis... IIAR Reflectance.•..

Input File: Enter the name of the input file or click on the File Selector button. The default fileextension is .img.

Output File: Enter the name of the output file or click on the File Selector button. The .imgextension is automatically added.

Coordinate Type: Click the appropriate radio button to select the type of coordinates to use. Ifthe input file does not have map coordinates, the coordinate type will automatically default to File.

Map Click to use map coordinates, if the data are rectified.

File Click to use file coordinates, which are pixels, starting with 0,0 in the upper leftcorner.

Subset Definition: Use this group to define a rectangular area of the data to be used as theoutput file. The coordinates of the subset may be derived from an inquire box in the Viewer or byentering explicit X,V values for the upper left and lower right corners of the subset. The defaultcoordinates are the entire input file.

From Inquire Box Click to define a subset area of the data by using the Viewer InquireBox. When you click this button, the coordinates below are updated with the coordinates ofthe cursor box in the Viewer.

To change these coordinates, you can move and/or resize the cursor box in the Viewer, thenclick this button again.

The image you are using and the inquire box must already be displayed in a Viewer in order touse the From Inquire Box option. Otherwise, you may manually enter coordinates in the fieldsbelow.

UL X: Upper Left X coordinate

UL Y: Upper Left V coordinate

LR X: Lower Right X coordinate

LR Y: Lower Right V coordinate

Ignore Zero in Output Stats. When this check box is on, pixels with zero file values will beignored when statistics are calculated for the output file.

OK Click to run this program with the options selected and close this dialog.

Batch Click to include this function in a batch file.

AOI ... Click this button and the Choose AOI dialog will display. This dialog lets you select anAOI (area of interest) in the image to which to apply this function.

Cancel Click to cancel this process and close this dialog.

View... Click this button and a Model Maker window will open and display the graphical modelused for this function. You can edit the graphical model from this Model Maker window for aspecific use.

You can also edit the Spatial Modeler Language script through the Model Maker window (selectProcess IGenerate Script from the Model Maker menu bar).

Help Click to see this On-Line Help document.

~ For information on using the ERDAS IMAGINE graphical interface, see the on-line IMAGINEInterface manual.

Lille Didier, Jost C

A decision support system for water resource management in

Lifou island, New Caledonia

In : Australasian remote sensing and photogrammetry

conference : conference program and abstracts. Adelaide :

Remote Sensing and Photogrammetry Association of

Australian, 2000, p. 61-74. Australasian Remote Sensing and

Photogrammetry Conference, 10., Adelaide (AUS),

2000/08/21-25.

a decision support system for water resource...

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